Method of burning or heat treating solid or fluid material



June 10, 194 1, E. A. ORRMELL METIIOD OF BURNING OR HEAT TREATING 'SOLID OR FLUIIJ MATERIAL 2 Sheets-Sheet 1 Filed May 6, 1939 INVENTOR:

Er'nst A'ron lsido r ORRMELL BY I ' ATTORNEY- June 10, 194-1. ORRMELL I 2,245,048

METHOD OF BURNING OR HEAT TREATING SOLID OR FLUID MATERIAL Filed May 6, 1939 2 Sheets-Sheet 2 INVENTOR:

Ernst Aron lsidor ORRMELL BY AMMMM ATTORNEY Patented June 10, 1941 ATE 1C Ernst Aron llsidor (Brrmell, Krarnfors, Sweden Application May 6, 1939, Serial No. 272,163 In Sweden December 21, 1938 8 Claims.

The present invention refers to a method of burning material or of treating solid or fluid material by heat whilst simultaneously exchanging heat between the combustion or heating zone and a temperature regulating gaseous or fluid medium. More specifically the invention is concerned with that kind of furnace in which the grate or grates are subjected to oscillatory movements.

Whilst as heretofore known a relatively slow reciprocating movement has been imparted to the hearth of the furnace, a far greater effect is obtained in the heat exchange between combustion or heating zone and temperature regulating medium, and in the steady movement or iiow of the material conveyed along the hearth, when, in accordance with this invention, stationary elastic vibrations of relatively high frequency are impressed upon the hearth Whilst, simultaneously, a temperature regulating medium is passed through channels provided .at or within the grate of the hearth. These channels will preferably be vibrated together with the hearth.

In certain cases, the temperature regulating medium may be applied for the purpose of raising the temperature of the material to be treated. If, for instance, a material which at a lower temperature tends to cling to the hearth is treated, it will be desirable or necessary to make use of the medium flowing through the pipes or channels of the hearth for the purpose of raising the temperature of the hearth.

In contrast, during the treatment of certain materials by means of heat, it may also happen that the material might burn fast to the hearth at a high temperature. In such cases, the temperature regulating medium may be used for cooling the hearth. When treatment at high temperature comes into consideration, or when a material is to be burnt, it may, in some cases, also be difficult or impossible to find a suitable hearth material, which, at such a high temperature, possesses suflicient heat resistance. In such cases too, cooling is of great practical value.

In other cases also, the temperature regulation of this invention may be of essential importance in order to provide for a treatment by heat or a combustion under the most advantageous conditions.

In the case of combustion, the vibrations impressed upon the hearth are of importance not only for the transmission of heat and the feeding of the material along the hearth but also for rendering the combustion more Vivid by the stirring of the material effected by the vibrations.

. upper hearth to a lower one.

Furthermore, these vibrations contribute to equalize the thickness of the layer of material supported by the hearth, thus, a uniform distribution of the material onthe hearth or hearths is obtained.

The transmission of heat to the temperature regulating medium, when the same acts as a cooling medium, may, according to the invention, be utilized in various ways.

The invention may advantageously be used for heating water, irrespective of whether this heating takes place in connection with steam generation or not. The invention may also be used for steam generation and also for drying or superheating steam, preferably of a pressure higher than six atmospheres above atmospheric pressure. After the treatment, the steam may be led to a steam boiler or another apparatus wherein its heat may be utilized.

When heating water in connection with the generation of steam, the Water, possibly coming from .a steam boiler, is caused to flow under pressure through the pipes or channels, provided at the grate or grates, and, after having been heated within these pipes or channels, may be led to a steam boiler, or, if the water had been supplied from a steam boiler, it will preferably be returned to the same boiler.

In all of the cases mentioned above, the water, or the steam, or both are advantageously led from one distribution chamber through two or more pipes to a second distribution chamber. In such a case, the method of this invention is preferably applied by causing a current of water, or of steam, or of both, to flow as uniformly as possible through a plurality or a group of pipes, coupled in parallel.

In certain cases, when material is to be burned, it may be convenient to return such material which had not been burnt after a feeding period of a certain length, and to admix such returned material with other material not yet burning.

In several cases, it will be advantageous to let the combustion of the material take place in two or more steps in such a manner that the material, after having been fed along one hearth or along a group of hearths, is conveyed along one or more additional hearths or possibly from an In such a case, the material that has been passed along one hearth or several hearths or groups of hearths, through which water, or steam, or both are led, if required, may be burnt on a hearth provided With openings, through which air is led. The air thus preheated is preferably used as combusanother distribution chamber.

tion air at a subsequent combustion zone of other material which is treated in the same manner thus advancing the combustion and the heating of water, or steam, or both.

In general, very good results have been reached by imparting to the hearths a vibration motion of a frequency higher than 760 a minute. In certain cases it is suitable to increase the frequency of vibrations to 1000 to 1160 a minute or even more.

By using the method of this invention, slag and quick ash will adhere to the hearth to a considerably less extent than to a stationary hearth. The method of this invention will yield especially advantageous results when used in plants for utilizing heat in connection with evaporation and combustion of waste lye, especially within the cellulose industry and preferably the sulphate cellulose industry.

The invention relates also to a furnace adapted to the carrying out of the method described above, said furnace being provided with one or more hearths preferably composed of pipes through which water, or steam, or both flow, and which are adapted to receive a vibration motion.

The pipes may be arranged substantially parallel to each other. The pipes, at least those parts which support the material, are mounted in a horizontal or nearly horizontal position. Suitably, the pipes are connected to a steam boiler. In this case, in accordance with the invention, a distribution chamber may be provided, connected to a steam boiler, with which distribution chamber a number of longitudinally extending pipes are connected at their one ends whereas the other ends of the pipes are connected with This last mentioned distribution chamber is then connected to the same or another steam boiler. In order to distribute uniformly the water, or steam, or both to the Various pipes, there may be provided Within the pipes reductions of their passage areas, choking flanges or the like. Such uniform distribution may in several cases also be obtained by making the pipes of a relatively small cross section or by providing a greater or smaller part of their lengths with a reduced cross section. Since, in some cases, part of each pipe is shaped as an elbow which forms an elastic connection with a stationary-not vibrated-distribution chamber, it will be convenient to construct these elbows of a smaller cross section, a greater elasticity and resilience of the connection being obtained thereby. In order to cause or to advance the fiow of Water, or of steam, or of both, through the pipes, these pipes may communicate with one or several pumps, or other means suited for such purpose.

The device may be constructed in such a way that either one or both distribution chambers are stationarily mounted and, thus, do not partake in the vibration. In this case, as the inlet for the temperature regulating medium is stationary too, the pipes must be connected to the inlet by means of flexible connections.

Those parts of the device upon which the vibration is impressed, are resiliently suspended, for instance in springs. An entirely elastic suspension may be used and the vibration may be transmitted to the grate in such a way that all points of the vibrating parts perform movements on. closed curved lines. This may be obtained, for instance, by means of a mechanically unbalanced or an excentric device or by electromagnetic means. The points vibrated may, however,

perform their movements on straight lines or other not closed lines. In addition to the vibrating motion, the hearths may be arranged to perform also additional movements, for instance for the purpose of cleaning. For such a purpose or for obtaining a uniform distribution of the material, there may also be provided special movable members.

The water, or the steam, or both, may, as mentioned above, be supplied to the various pipes by means of pumps. In such a case the pressure within the pipes should preferably be lower than the pressure in the distribution chamber to an extent that under all working conditions a sufficiently uniform distribution of the temperature regulating medium will be ensured.

On the accompanying drawings, some embodiments of the device according to the invention are illustrated by way of example, partly in View, partly in section.

Fig. 1 is a vertical section of a steam boiler combined with a vibrating grate,

Fig. 2 shows, also in vertical section, another steam boiler construction with vibrating grate,

Fig. 3 is a vertical section of a roasting furnace with vibrating hearths.

Fig. 4 is a section on line i-fl of Fig. 3.

The same reference numerals refer to the same details in the various figures.

In the device shown in Fig. 1 the grate is composed of parallel steel pipes l which at their ends are connected to chambers 2 and 3, respectively. The pipes l are elastically supported by means of springs 3, 5, and are connected by an appropriate link to a vibrator 6 which, likewise, is supported resiliently by means of springs. Consequently, a vibrating motion is forced upon the pipes l which is operative in vertical planes extending along the longitudinal axes of the pipes.

Beneath the pipes, there is a box 1 provided with an inlet 8 through which, for instance by means of a fan, combustion air is supplied, which then flows upwardly between the pipes. The fuel is supplied through the pocket 9 and is fed forwards over the pipes I by their vibrating motions. Water from the lower boiler I0 is fed through the pipe H via the pump I2 to the distribution chamber 2. In order to provide for an even distribution of the water to the pipes I, the pipe portions 53 connected to the distribution chamber 2 are of a smaller cross section than the remaining lengths of the pipes l. The water then passes through pipes l, chamber 3, and through conduit it to the upper boiler l5. In the example shown, box 7 takes part in the vibrations, but it may also be stationarily mounted beneath the pipes. In the embodiment shown, chambers 2 and 3 are stationary, but they may also be arranged to vibrate together with the pipes I. It is also possible to cause the water to flour by self-circulation, the pump l2- thus being superfluous. Preferably, pipes i should have a relatively small cross section, in order to increase their resiliency which is important in this case, since the said pipes are rigidly connected with the chambers 2 and 3. The resiliency is ,further increased by forming the pipe elbows l3 of a smaller cross section than the other parts of the lengths of the pipes i.

In the boiler construction shown in Fig, 2 the grate is similar to that of l. The chambers 2 and 3, however, are located at the same side with regard to the pipes l. These pipes extend from chamber 2 to the pocket 9, Where they are connected in pairs by arched parts and then return to chamber 3, from where the utilized cooling medium, water, or steam, or both are led away and used in any suitable manner.

The roasting furnace shown in Figs. 3 and 4 consists of a vertical shaft Mi having a rectangular cross section, to which the material to be roasted is supplied frorn above by means of a conveyer M, from which the material falls down over a lid or flap 42 provided with a counterweight 43. The hearths are formed by or composed of pipes 44, which extend from two distribution boxes E5 provided at the bottom of the shaft, one at each of two opposite vertical shaft walls. The pipes 44, at first, follow one wall, for a certain length, then extend horizontally from this Wall to the opposite wall, follow this latter Wall for a certain length and then extend horizontally to the first mentioned wall and so on. The horizontal portions of the pipes form the hearths, and every second pipe in each hearth is connected to the same distribution box. The pipes 44 open into two distribution boxes 46 in the upper portion of the shaft, from which boxes the medium that has passed through the pipes is led off through pipes 41 and t8 and may be used for heating purposes. All hearths are thus formed by one and the same pipe system which simultaneously cools the shaft walls. The hearths decline from the shaft Walls towards the centre of the shaft, and they may have different slopes, respectively. The pipes 21 and 48, at their upper ends are provided with flanges $9, and compression springs 5! are provided between said flanges and stationary supports 5@, the whole pipe system with hearths and distribution boxes thus being elastically suspended. An elastically supported vibrator 52 imparts a vibrating motion to the pipe system. The cooling medium, which preferably consists of water, is supplied to the distribution boxes 45 through pipe 59.

The materials to be treated, for instance iron pyrites, are fed to the kiln shaft by means of conveyer M and fall down upon the upper hearth. Owing to the vibrations impressed upon the hearths and to the slopes of the hearths alternating in opposite directions, the material is fed along the hearths perpendicularly to the longitudinal direction of the pipes and down from each hearth to the next located below. The material is finally led away through the outlet 53. Combustion air is supplied through the inlet 54 and further from the pipe 55 through the openings 56 provided in the shaft wall (secondary air). Openings 5? for inspection are provided within the shaft wall. The roasting gases escape through flue 58, which is arranged beneath conveyer H, and will thus preheat the material fed to the grates of the kiln by said convey-er.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The method of treating, by means of heat, material, such as pulverulent material, or solutions or suspensions for evaporating the solvent contained therein, or of burningmaterial by passing said material in a countercurrent to a current of a hot gaseous medium upon and along at least two grates arranged at different levels and one grate substantially above the other and at a distance therefrom, said method including the step of imparting to said grates stationary elastic vibrations of relatively high frequency for feeding said material along each one of said grates and by free fall from one grate to the next, whilst simultaneously exchanging heat between the zone of said grates heated by said cur-- rent of a gaseous medium and a temperature regulating medium flowing through channels provided within said grates.

2. In a furnace for treating, by means of heat, material, such as pulverulent material, or solutions or suspensions for evaporating the solvents contained therein, or of burning material, the combination with at least one grate of means for resiliently mounting said grate, a vibrator, means for resiliently supporting said vibrator, link means for vibrating said grate from said vibrator, said grate composed of pipes, a stationary inlet casing associated with said pipes and flexible conduits for connecting said inlet casing with said pipes, said pipes and said inlet casing adapted to pass a temperature regulating medium therethrough.

3. In a furnace for treating, by means of heat, materials, such as pulverulent material, or solutions or suspensions for evaporating the solvent contained therein, or of burning material, at least two grates arranged at different levels, one substantially above the other and at a distance therefrom, means for elastically suspending both said grates, said grates provided with channels for the purpose of passing a temperature regulating medium therethrough, a vibrator, means for elastically supporting said vibrator, link means for vibrating said grates from said vibrator for the purpose of feeding said material supported by said grates along said grates and in free fall from one of said grates to the next.

4. A furnace as set forth in claim 3, said gratesprovided with openings for permitting a current of hot gaseous medium to pass therethrough.

5. In a furnace for treating, by means of heat, material, such as pulverulent material, or solutions Or suspensions for evaporating the solvent contained therein, or of burning material, in combination, at least two grates arranged at different levels one substantially above the other and art a distance therefrom, means for elastically suspending both said grates, said grates composed of pipes horizontally arranged, said pipes for the purpose of passing a, temperature regulating medium therethrough, a vibrator, means for elastically supporting said Vibrator, link means for vibrating at least part of said pipes from said vibrator for the purpose of imparting to the particles of said material supported by said grates impulses in planes considerably different from the respective planes of the surface of said grates, and for causing the particles of said material to move along said grate surfaces and in free fall from one grate to the next.

6. In a furnace as set forth in claim 5, said grate composing pipes being connected in pairs by arched parts at their one ends, at least two stationary distribution chambers arranged at the side of the other ends of said pipes, one end of each of said pipe pairs connected with one of said distribution chambers, the other end of each of said pipe pairs connected with the other of said distribution chambers, respectively.

7. In a furnace for burning, or otherwise treating by means of heat, material, the combination with at least one grate composed of pipes substantially horizontally arranged and located adjacent and parallel to each other, of means for elastically supporting at least part of said pipes, means for causing a, cooling medium to pass through said pipes, a vibrator, and means for connecting said pipes with said vibrator for the purpose of vibrating said pipes from said vibrator "jacent and parallel to each other, of means for elastically supporting'at least part of said pipes,

means for causing a cooling medium to pass through said pipes, a vibrator, and means for connecting said pipes with said vibrator for the purpose of vibrating said pipes from said vibrator and imparting to the particles of said material supported by said grate, impulses in planes,

considerably different from the plane of the surface of said grate and for causing said particles to move along said grate surface, the pipes on a certain part of their length at one of their ends, being of a smaller diameter than at the remainder of their lengths.

ERNST ARON ISIDOR ORRMELL. 

